Speaker
Description
Future gravitational-wave observatories, including next-generation ground-based detectors and LISA, will enable precision measurements of black hole quasi-normal mode frequencies. In realistic astrophysical settings, however, black holes are not perfectly isolated: surrounding environments, for example stars or dark matter, can source external tidal fields that deform the QNM spectrum. In this talk, I will present a general perturbative framework to compute these frequency shifts at linear order, providing a systematic description of how weak external fields modify black hole ringdown. I will discuss the resulting phenomenology, including the breaking of isospectrality and other observable signatures relevant for black hole spectroscopy. As a nontrivial validation of the formalism, I will show that it successfully reproduces the known QNM spectrum of slowly rotating Kerr black holes. I will conclude with remarks on spectral instabilities from an exact WKB perspective, and the extent to which they affect the robustness of our perturbative predictions.
| Other topic / keywords: | Ringdown, quasi-normal modes, black hole spectroscopy |
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